Many electronic products require an operating voltage satisfying their specifications of voltage, so as to drive their internal circuits to achieve normal operations. In general, a charge pump is used as a booster to output a proper operating voltage to electronic products. For example, a charge pump is used to convert an input voltage having the low potential to a working voltage having a high potential. One of the conventional charge pumps is the Dickson charge pump.
Dickson charge pump is a multi-stage charge pump having a plurality of diodes and capacitors, with each capacitor being driven by a clock signal. An input voltage of Dickson charge pump will rise stage by stage, so as to provide high-potential output voltage to electronic products. However, the number of diodes and capacitors included in Dickson charge pump is fixed. That means the number of stages of Dickson charge pump is fixed. In such structure, Dickson charge pump only outputs a fixed operating voltage while an input voltage is input to Dickson charge pump. Dickson charge pump cannot regulate the potential of the operating voltage randomly according to the actual product requirements or specifications.